1. Field of the Invention
This invention relates to liquid crystal compounds and compositions.
2. Description of the Prior Art
There have been known several ferroelectric liquid crystals, such as 2-methylbutyl ester of 4-n-octyl-4'-biphenylcarboxylic acid (hereinafter referred to as Compound A) (page 111, Preprint of the 10th Symposium on Liquid Crystals, 1984) and p'-(1-methylheptyloxycarbonyl)phenyl ester of 4-n-octyloxy-4'-biphenylcarboxylic acid (hereinafter referred to as Compound B) (page 173, Preprint of the 11th Symposium on Liquid Crystals, 1985).
However, the value of spontaneous polarization of Compound A is small (smaller than 10 nC/cm.sup.2), though the compound shows a chiral smectic phase of ferroelectricity at a temperature near the room temperature. On the other hand, Compound B has larger value of spontaneous polarization (80 nC/cm.sup.2), but mesomorphic temperature range of the compound is much higher than the room temperature (72.5-121.5.degree. C.).